In the field of general industrial drive applications, regardless of motor design and system design, improve the efficiency of saving energy should be put in important position. It is reported that more than % of the nation's electricity is consumed on the motor running, thus improve the efficiency of the motor, is very meaningful. The data did comparative analysis, for. KW asynchronous motor system efficiency can reach. %, but also the capacity of brushless dc motor efficiency can reach. %。 The above analysis it can be seen in all types of motor, brushless dc motor loss minimum, the highest efficiency. With the progress of electronic technology, the development of electronic industry, electronic components of the price declining. Considering comprehensive index (The system performance, weight, energy consumption, etc. )After the application of brushless dc motor is in the rising trend. Comprehensive properties compared with other motor are listed in the table below: mechanical properties of overload capacity controllable electromagnetic interference noise maintainability life volume efficiency cost of ac asynchronous motor soft grew up a little difficult to less than the size is low with big hard brush dc motor to good big serious difficulty better short lower high hard brushless dc motor with a good little easy long gao high above analysis we can see that in industrial applications, quickness, controllable in brushless dc motor (BLDCM), reliability, small volume, light weight, energy saving, efficiency, tolerance has obvious advantages in environment and economy, etc. In recent years, along with the rare earth permanent magnet materials and power electronic device price performance ratio, as small and medium-sized power high performance brushless dc motor (BLDCM) speed control motor and servo motor in the industrial application is more and more widely. Here are some typical applications in industrial analysis. Industrial application of classification of constant speed drive machinery general industrial occasions do not need to control field in the past are mostly adopts three-phase or single phase ac asynchronous and synchronous motor. ()Single direction load of continuous running mostly adopts ac asynchronous induction motor, capacitor transformation of single phase or three phase ac asynchronous motor. Does not need speed or allow speed changing with load slightly high or medium speed machinery, such as water pump, fan, compressor should select corresponding speed asynchronous motor is very or extremely; ()The requirements of small volume, light weight and high operating speed,Cases such as higher than r/min)Load such as mixer, vacuum cleaner and cleaning the carpet washing machine, the more the single-phase series motor or dc motor directly driving load; But that small noise of high-speed driving, can consider to choose by the inverter power supply of the intermediate frequency induction motor or brushless dc motor by the dc power supply. ()For smaller power, and speed tolerance larger small mechanical work, can choose cheaper cover pole type asynchronous motor. ()To speed lower working machinery, in particular often frequent positive &negative adjustment, in order to shorten the transition time, improve production efficiency, lower noise, can be used in a direct drive at low speed, choose electromagnetic speed synchronous motor at low speed asynchronous motor or gear reduction. Such as automatic doors and high-power mixer. According to the size of the door load, choose from dozens of watts to several hundred watts of electrical power in constant speed control of the above application, the power is not greater than the kW and continuous operation, in order to reduce the volume and save material, improve efficiency and reduce the energy consumption of these factors, a growing number of motor is being gradually take the place of brushless dc motor. And in the power of the larger situation, because of its high cost and investment, in addition to the permanent magnet drive, increase also fewer applications.
